Triton 5.4L automatic transmission

This truck has a problem.
First let me say that it isn't my truck, but it is my dad's. It has just under 80,000 miles.

The problem is that it stalls. The engine won't idle over 500 rpm, and usually it dies.

A while ago, the CEL came on, and we took it down to Advance auto parts and they said cylinder 6 misfire. They erased the code and it hasn't come back on since. Monday, the CEL came back on and this time it read no codes. When I was at Advance Auto parts, the truck wouldn't start. It would turn over, but wouldn't start. The guy got some starting fluid and it started, but died when he stopped spraying. like 20 minutes later the truck started and I brought it home and we haven't drove it since.

We took it to Ford sometime last year. They replaced the COP and spark plug. The problem went away and came back like a week later. I have replaced every spark plug, as well as that COP again.

I am led to believe that this is a fuel problem. There is a reason too.

The previous owners had installed a remote start system. The remote doesn't work, so it is basically useless. They spliced the wire into the cylinder 6 fuel injector. I plan on removing it. I checked the resistance and compared it to the other fuel injectors and they seem to be the same. I didn't notice any difference.

oh and when I replaced the spark plugs, some of the back spark plugs had oil over the top of them. Not sure what this either... I am hoping that the head gasket isn't bad. speaking of which, I never did check the oil for coolant. I will do that later.

I think I pretty much covered everything...

Thanks for the help, anything is appreciated. I have been trying to figure out what was wrong with the truck for a while now and haven't really gotten anywhere.

We need the truck because my car got totaled and it is sitting on our trailer. 1987 5.0 mustang.

I guess I posted this in the wrong area... going to repost in the v8 section

 

Posted this in the 1997-2003 F-150 area, so mods can delete that one I guess.

Triton 5.4L automatic transmission

This truck has a problem.
First let me say that it isn't my truck, but it is my dad's. It has just under 80,000 miles.

The problem is that it stalls. The engine won't idle over 500 rpm, and usually it dies.

A while ago, the CEL came on, and we took it down to Advance auto parts and they said cylinder 6 misfire. They erased the code and it hasn't come back on since. Monday, the CEL came back on and this time it read no codes. When I was at Advance Auto parts, the truck wouldn't start. It would turn over, but wouldn't start. The guy got some starting fluid and it started, but died when he stopped spraying. like 20 minutes later the truck started and I brought it home and we haven't drove it since.

We took it to Ford sometime last year. They replaced the COP and spark plug. The problem went away and came back like a week later. I have replaced every spark plug, as well as that COP again.

I am led to believe that this is a fuel problem. There is a reason too.

The previous owners had installed a remote start system. The remote doesn't work, so it is basically useless. They spliced the wire into the cylinder 6 fuel injector. I plan on removing it. I checked the resistance and compared it to the other fuel injectors and they seem to be the same. I didn't notice any difference.

oh and when I replaced the spark plugs, some of the back spark plugs had oil over the top of them. Not sure what this either... I am hoping that the head gasket isn't bad. speaking of which, I never did check the oil for coolant. I will do that later.

I think I pretty much covered everything...

Thanks for the help, anything is appreciated. I have been trying to figure out what was wrong with the truck for a while now and haven't really gotten anywhere.

We need the truck because my car got totaled and it is sitting on our trailer. 1987 5.0 mustang.

 

Change the fuel filter, clean the throttle body and IAC. Check the fuel pressure at the Schrader valve on the fuel rail.

 

The fact that it started when starter fluid was sprayed in the intake, and dies when he stopped spraying makes me think it is probably fuel. Cleaning the throttle body is easy and free (clean the MAF sensor while you are at it, use only MAF sensor cleaner as this is a delicate piece), replacing the fuel filter probably needs to be done anyhow. If you have good pressure, may be fuel injectors.

edit: also, check throttle position sensor. I had the dealership run a diagnostics when mine was running rough and was told my "TPS was out of range" I replaced the TPS and cleaned my throttle body. It did wonders.

 

My truck did the same thing a while back, after some investigating, I was told when it wouldnt start, give the IAC a good smack. so i did, its kinda tuff to hit I think I used a tire iron, or breaker bar, anyway something long enough to reach it and give it a good hit,(without breaking anything). After a smack or two the truck would start. So i replaced the IAC and all was well. So its worth a shot, if it wont start give it a hit and see if it helps. If it starts, replace the IAC. Kind of a hillbilly test, but hey it works. lol

 

Introducing a combustable into the intake and getting a run is clear indication no fuel in being injected into the cylinders.
At this point only work on it as a fuel problem.
First thing is to test for fuel pressure at the test port on the fuel rail.
.
Causes of no fuel;
Pump is faulty.
Pump relay with faulty contacts.
Crash sensor faulty.
Cam position sensor or plugup is intermittant.
.
Filter won't act as you discribe.
Until these tests are done you have no positive info to go on.
Very often a fuel system issue has no way to set a code.
Get the remote start connections off without creating additional problems or you will have a hassle with more than one problem at the same time.
Good luck.

 

yeah I had a feeling about the IAC. My dad doesn't want to get a new fuel filter, he says to just test the one we have. Which I really don't want to do. it is probably time to replace it anyways, and its pretty cheap too. I have to go to the parts store anyways.

I also had a feeling about fuel too. I will see if we have a fuel pressure gauge.

The TPS didn't throw a code, so I am assuming it isn't bad. I will probably check the voltage tomorrow though, it's a quick test.

Probably try to clean the TB as well.

 

I don't think it is a problem with the spark. I think it is either a fuel problem or an air problem. You have to have the throttle open to get the starter fluid in there, so maybe the IAC is bad. I am going to try to test the fuel pressure and maybe clean the TB. I want to test the IAC but don't want to take it off because I can't get a new gasket without buying a new IAC.

I am leaning towards a fuel pump, IAC, or maybe some injectors. I don't think it is a fuel filter, but it's only like 10 bucks.

 

If it is the IAC not allowing normal start, you would be able to keep the motor running with the throttle and be able to drive away.
When the motor is hot, even without the IAC open, the motor would still attempt to start and run at a lower rpm such as about 550 +/-.
To test for IAC operation; if the motor can be started at anytime, remove the IAC plug with the motor at idle.
If the idle drops low (a normal condition) the IAC is working at that time.
The reason for this action is two fold.
The throttle plate stop is set to 'not' allow the throttle to go completely closed so it allows some air to pass (the low idle above) and also not to stick in the bore after the motor cools.
The IAC operation allows enough 'extra' air so the computer has full time 'adjustment range' so the idle can be held to about 750 rpm +/- 50 rpm, above the low mechanical low setting.
Good luck.

 

oh yeah lol you can unplug it...
can't believe I didn't think of that... I did it all the time on my car...
Anyways, I will test this tomorrow. The truck does stay on if you hold the gas pedal. You have to left foot brake in order to keep it from stalling.
If the truck dies when the IAC is removed, then it should be ok. If it stays the same, then the IAC needs to be replaced. Am I correct on this?

 

Oh please - I didn't know cheap bastards like that still existed. Get a Motorcraft filter if possible, aftermarket filters don't always fit right and can be a bear to get back off. However, you should be safe with a Purolator or Wix - just DON'T get a Fram. You have the clip tools?

Autozone should have a fuel pressure gauge in their loaner tool kit.

Remove the TB to clean it, and use TB cleaner. The best stuff to clean the IAC with is WD-40, work the plunger with a screwdriver.

 

yeah I know... its only like $10 bucks too
I don't think I will remove the IAC because we would need a new gasket, and the parts store doesn't sell those separate.

I will run some tests here on the IAC and the TPS and maybe some other things. If I find nothing, I will probably bring it down to Advance. Their online store doesn't list the part, but they might have them anyways. I have to go anyways for another car, so why not ask and have them run the tests.

 

Gaskets are reusable for the IAC and they usually come off in one piece. You can remove the IAC on the 5four without removing anything but the air intake.

Also, a new IAC comes with a new gasket, -so you know.

 

I know the new ones come with a new gasket. I just didn't know they were reusable.

 

Yea, those are. Unless they rip. Generally they don't. I never had one those give me a problem. On top of the engine, you should replace gaskets from the Plenum down if your running an aluminum manifold. But everything on top of that can be used again, IF they are indeed in good shape and one piece of course. The only sticky gasket on top is the metal EGR gasket.